Wireless security networks, industrial data buses, automotive networks, and many other applications may use wireless communication for transmission of critical high priority messages.
It may be assumed that the wireless medium is error prone (e.g., due to noise and interference) and susceptible to collisions, which may occur when two or more nodes attempt to transmit at the same time. The network may use a Time Division Multiple Access (TDMA) communications protocol and time synchronization may fail.
Multiple channels may be available for transmission. There may be several existing methods to address this problem, such as, for example (a) use of acknowledgements to confirm the delivery of the message; (b) use of Carrier Sense Multiple Access (CSMA) communications protocol and exponential backoff to reduce the chances of collision; and (c) transmission on alternate frequencies or channels to avoid noise and interference.
As wireless networks are used in new applications, techniques for reliable and timely delivery of messages may gain importance. A wireless network may be used, for example, to send fire or burglar alarms from detectors to a central controlling station in homes or offices. In a hospital or old age home, wireless links may be used for devices that send emergency messages. Future automobiles may use wireless communication between sensors and airbags. However, in order for wireless networks to gain increased acceptance, problems like collision, noise, and interference may need to be addressed adequately.
In case of no collisions, the message may need to be communicated with the least latency. If multiple nodes have a message to be sent, the latency for the message increases due to collisions.
There are various methods for providing message delivery in data networks. For example, the Transmission Control Protocol (TCP) communications protocol has been deployed for the Internet for many years. The Transmission Control Protocol (TCP) uses acknowledgements to confirm the delivery of messages. The Carrier Sense Multiple Access (CSMA) communication protocol has been used for Ethernets. According to the Carrier Sense Multiple Access (CSMA) communication protocol, the sender listens on the shared medium and transmits only when the channel is free from other transmissions. The Carrier Sense Multiple Access (CSMA) communication protocol may help in reducing collisions in the network. Ethernets may also use exponential backoff to further reduce the chances of collision. Each time the transmission fails, the sender may use exponential backoff with increased wait intervals.